Knife sharpener



F. R. CHESTER KNIFE SHARPENER Aug. 21, 1951 2 Sheets-Sheet l Filed Dec. l5, 1948 INVENTOR.

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F. R. CHESTER KNIFE SHARPENER Aug. 2l, 1951 Filed Dec.v

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rTOQA/Ex Patented Aug. 21, 1951 UNITED STATESl PATENT OFFICE KNIFE SHARPENER `Frank R. Chester, Santa Monica, Calif.

Application December 13, 1948, Serial No. 65,054

(Cl. 'Y6-86) 3 Claims.

My present invention relates to Sharpeners, particularly adapted for sharpening knives and similar cutlery.

One of the principal objects of this invention is to provide a Sharpener of this class which is particularly simple and economical of construction proportionate to its functions, and also simple in operation by merely drawing the knife or blade through the Sharpener.

Another important object of this invention is to provide a Sharpener of this class which is automatic in operation, in that it presents a new sharpening portion whenever a knife or blade is drawn therethrough for sharpening purposes.

A novel feature of this invention is to provide means for carrying out the foregoing object, namely, by periodically rotating a rotatable sharpening wheel.

A further important object of this invention is to provide a sharpener which is so constructed that the sharpening element may be readily renewed.

A still further important object of this invention is to provide a Sharpener of this class having a novel and simple means for limiting the position or depression of the knife or blade, when drawing it through the Sharpener, with respect to the sharpening element, in order to prevent unnecessary gouging of the knife, or other blade, so as to provide relatively uniform sharpening thereof.

With these and other objects in View, as will appear hereinafter, I have devised a knife sharpener having certain novel features of construction,

combination, and arrangement of parts and portions, as will be hereinafter described in detail, and particularly set forth in the appended claims, reference being had to the accompanying draw ingsand to the characters of reference thereon, which form a part of this application, in which:

Fig. l is a side elevational View of a knife Sharpener embodying my invention in a preferred form, portions being broken away and in section to facilitate the illustration;

Fig. 2 is a transverse sectional elevational View thereof, taken through 2 2 of Fig. 1;

Fig. V3 is a partial sectional elevational view thereof, taken through 3 3 of Fig. 2;

Fig. 4 is an enlarged sectional View thereof, taken through 4*@ of Fig. 2, showing the form of limiting means for the knife to be sharpened;

Fig. 5 is a partial elevational and partial sec,- tional view of a knife Sharpener embodying my invention in a slightly modified form;

Fig. 6 is a sectional elevational view of the yg Il I) 2 modified form, taken through 6-'6 of Fig. 5; and,

Fig. 7 is a fragmentary sectional view thereof in plan, taken through 'I-'I of Fig. 5.

The housing of the Sharpener, shown in Fig. l, consists preferably of a casting I having a recess I a at one side, and a cover plate 2 secured by screws 3 to one side of the casting I, over the recess I a therein. The housing member I and the cover plate 2 have vertical transverse slots Ib and 2a, respectively, to permit the knife, to be sharpened by the device, to be drawn transversely through the housing. Both of these slots diverge outwardly at their upper ends to facilitate the introduction of a knife, or other blade, into said slots.

Within the housing, and specifically Within the recess Ia thereof, is mounted a U-shaped cage 4, the legs of which are positioned adjacent the inner wall of the recess and the inner side cover plate 2. This cage is movable vertically Within the housing and rests at the opposite ends of an upwardly bowed leaf spring 5. Y

Within the cage is positioned the sharpening element S, which consists of a plurality of star wheel elements 6 and I placed against each other but axially aligned. At the outer sides of the star wheel elements positioned in this manner are discs B. The star Wheel elements and discs are secured together by pins or rivets 9. These members are secured together in such a manner that the star wheel elements are staggered with respect to each other, that is, so that the teeth of the star wheel elements 'I are circumferentially spaced from the teeth of the star Wheel elements 6, as shown best in Fig. 1, thereby providing sharp V-shaped slots or grooves between the teeth of each ofthe elements, or sharp V-shaped slots between adjacent teeth of the star wheel. The adjacent edges of the teeth are flat and present keen sharpening edges for sharpening a knife, or other blade, drawn through the grooves. The sharpening star wheel just described is rotatably mounted on a pin I6 which is supported at its ends in the opposite walls or legs of the cage 4. Thus, the star wheel is moved vertically with the cage within the housing and is normally urged in an upper position by the spring 5.

Within the housing is mounted a resilient pawl II. The upper end of the pawl is held by the end wall of the housing member I, and the lower end has a pawl portion IIa which extends resiliently between and engages adjacent teeth of the star wheel for temporarily holding the star Wheel against rotation.

As a knife or blade is forced downwardly between adjacent teeth, which are aligned with the slots lb and 2a, and drawn across the device, the sharpening element is forced downwardly with the cage 5 causing the pawl portion Ila to be ejected from the groove between two of the teeth and allowing the sharpening clement to be forced downwardly to produce the desired force against the knife, allowing the pawl portion I Ia to enter the next upper groove in the sharpening element. As the knife is withdrawn, the sharpening element is urged upwardly by the spring, simultaneously causing the sharpening element, or star wheel, to be rotated to present a new sharpening portion to the next knife or blade drawn through the device.

The housing member l carries a pair of balls l2 which are positioned opposite each other, and the adjacent portions thereof are located within the slot Ib. These balls engage each other at the median portion of the slot Ib and substantially at the vertex of the groove between adjacent teeth of the star wheel when the latter is depressed. These balls guide the knife or blade through the sharpening device, facilitate the limiting of the low position or depression thereof, and also tend to cause a swedging action against the bevelled or sharpened faces of the knife or blade.

The modified structure, shown inFigs. 4 and 5, is enclosed in a housing made of duplicate housing members 2'I which may be pressed of sheet metal and secured together by screws 22. These housing members also have transverse slots Zia whichV extend downwardly from the upper portion of the housing. Within the housing is also positioned a cage 23 which is movable in a vertical direction and rests at its lower portion on the upper ends of a leaf spring 24.

Within the cage is located a star wheel sharpening element 25 which is constructed similar to the star Wheel S described above, but in this instance the star wheel sharpening element is rotatably mounted on a shaft or mandrel 26 which is ixedly mounted on the walls of the housing members 2l, that is, in such a position that it cannot move vertically. But in this instance the cage 23 may be moved vertically with respect to the sharpening element. The lateral edges of the cage 23 have Iianges 23a which are slidable against the inner sides of the end walls of the housing members to facilitate the vertical guiding of the cage. The side wall of the cage, which slides against the inner side of the side walls of the housing member, has a narrow slot 231 which is positioned opposite the slot 2|a for seating the sharpening edge of the knife, or other blade. Two of such slots 23b may be provided if the cage 23 has side walls against the inner sides of both housing members 2 l. As shown, the cage 23 also has an elongated vertical slot 23c to prevent the mandrel 26 from interfering with the vertical movement of the cage.

One end of the cage has a pawl 21 the lower end of which is secured to the bottom portion of the cage, and the upper end of which has a pawl portion 2la which is adapted resiliently to extend into the groove between adjacent teeth of the star wheel sharpening element.

In this instance the knife or blade to be sharpened is pressed against the upper portion of the cage with the sharpening portion in the slot 23h. As the knife or blade is drawn across the sharpening element, the cage is depressed carrying with it the pawl 21. When the cage is released by withdrawing the knife, the upper movement of the pawl portion 2la causes the sharpening element to be rotated one notch.

I wish it to be understood that I do notdesire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

I claim:

1. In a Sharpener of the class described, a housing having a transverse knife slot at one end, for receiving a knife to be sharpened, a cage mounted in the housing and movable therein with respect to the slot, a star sharpening wheel rotatably supported by one of the former and located within the cage, the knife, when inserted into the sloty being capable of being drawn transversely through the wheel between adjacent teeth, a spring located within the housing and normally urging said cage toward the slot, and a pawl normally resiliently engaging the star wheel for rotating the wheel as the knife is withdrawn from the slot.

2. A knife Sharpener, comprising: a housing having a transverse knife slot in its upper end through which a knife to be sharpened can be drawn; a cage slidable vertically within said housing; a sharpening wheel rotatable on said cage and having circumferentially-spaced teeth between which the knife in said slot can be drawn; a spring disposed in said housing beneath said cage and normally urging the same upwardly and resisting downward movement of saidv cage and said wheel due to a downward force applied by the knife against said wheel; and a resilient pawl mounted within said housing and extending substantially tangentially of said wheel, said pawl being adapted to engage a tooth of the wheel as the latter is raised by said spring, following each sharpening operation, so as to index said wheel to dispose successive tooth spaces of said wheel in alignment with said slot.

3. A knife Sharpener, comprising: a housing having a transverse knife slot in its upper end through which a knife to be sharpened can be drawn; a cage slidable vertically within said housing; a sharpening wheel rotatable on said cage and having circumferentially-spaced teeth between which the knife in said slot can be drawn; means for retaining said wheel in various positions of rotary adjustment so as to align any of said tooth spaces with said slot; resilient means disposed within said housing and engaging said cage so as to urge the latter upwardly; and stop means for limiting the upward movement of said cage.

FRANK R. CHESTER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 450,215 Bradford Apr. 14, 1891 457,965 Bradford Aug. 18, 1891 1,552,167 Johnson Sept. 1, 1925 FOREIGN PATENTS Number Country Date 171.833 Great Britain Jan. 18, 1921 

